A simple transformer is composed of a closed permeable magnet and two windings. One of the windings is connected to the AC power source, called the primary winding Np, and the other winding can be connected to the load, called the secondary winding Ns.
If the primary winding is connected to the power supply of the AC voltage Ui, the transformer is in no-load, and the alternating power Io is generated in the primary winding, and Io is called the no-load current. This current establishes an alternating magnetic flux that is closed along the magnetic circuit of the magnetic core. The magnetic flux passes through the primary winding and the secondary winding at the same time. The self-induced electromotive force E1 is generated in the primary winding, and the secondary pole generates a mutual induction electromotive force E2, then E1:E2 =Np:Ns. Np is the number of turns of the primary winding, and Ns is the number of turns of the secondary winding.
Transformers play a role in step-up, step-down, isolation, rectification, frequency conversion, phase inversion, impedance matching, inversion, energy storage, and filtering in electronic circuits.
A Classified by working frequency:
Power frequency transformer: working frequency is 50Hz or 60Hz
Intermediate frequency transformer: working frequency is 400Hz or 1KHz
Audio transformer: working frequency is 20Hz or 20KHz
Ultra audio transformer: above 20KHz, not more than 100KHz
High-frequency transformer: The working frequency is usually above KHz to hundreds of KHz.
B Classification by purpose:
Power transformer: a transformer used to provide the power required by electronic equipment
Audio transformer: transformer for audio amplifier circuit and audio equipment
Pulse transformer: a transformer that works in a pulse circuit, and its waveform is generally a unipolar rectangular pulse wave
Special transformers: transformers with a special function, such as parametric transformers, stabilized transformers, ultra-isolation transformers, transmission line transformers, and leakage transformers
Switching power supply transformer: used for transformers in switching power supply circuits
Communication transformer: a transformer used for blocking and filtering in a communication network
Folding material
Electronic transformer materials mainly include
Skeleton (Bobbin, Base, Case)
Copper Wire
Ferrite Core (SI-Steel Lamination)
Copper Foil
Insulating tape (Tape)
Safety tape, also known as Margin Tape
Tube
Chemical materials: solder (Solder Bar), insulating oil (Varnish), glue (Epoxy, Glue), thinner (Thinner), flux (Scaling Powder), ink (Ink)
Folding process
1) Pre-processing, such as copper foil, frame and other pre-processing; (beforehand process)
2) Winding coil; (winding coil)
3) Termianl lead wire;
4) Solder one; (dip solder 1)
5) Combination magnetic core, including glue and tape; (assembly)
6) Test one; (test 1)
7) Baking glue; (bake glue)
8) Immersion; (dip varnished or vacuumed varnish)
9) Bake varnish; (bake varnish)
10) solder two; (dip solder 2)
11) Test two; (test 2)
12) Visual inspection and cleaning; (inspection&cleaning)
13) Finished product packaging; (packing)
Note: This process is a general process, and some processes for specific products can be deleted.
Folding performance index
A. Inductance
B. Leakage Inductance
C. DC Resistance
D. Turn Ratio (Turn Radio)
E. Withstand voltage (Hi-POT)
F. Insulation Resistance
G. Mechanical Dimension
H. Layer Insulation
I. In Circuit Test